The present invention relates to an image recorder having a charging unit, an exposing unit, a developing unit, a transferring unit, a cleaning unit and other image forming process units which are arranged around a photoconductive element which may be implemented with a drum or a belt.
With the spread of image recorders such as a laser printer and a facsimile machine, there has recently been developed a personal image recorder which allows a user not only to supply toner, or developed, but also to replace a photoconductive element and a cleaning unit without the help of a serviceman. This kind of image recorder usually includes a photoconductive element, and a charging unit, a cleaning unit and other image forming process units which are arranged around and constructed integrally with the photoconductive element. When a predetermined period of time expires, when any of such units fails, when the developer runs out, or when the cleaning unit becomes full of toner collected, those units which are unitary with each other are bodily removed from the image recorder and individually replaced with new ones. This replacement system, however, has some problems left nusolved, as follows. The cost per replacement with respect to the individual structural elements is high increasing user's burden. Since the lives of the photoconductive element, developing unit, cleaning unit and others are different from each other, the photoconductive element, for example, which is comparatively expensive has to be discarded when the lives of the developing and cleaning units expire even if it is still usable. Such wastage adds to the cost per print.
In the light of the above, there has been proposed an image recorder in which the major process units other than the photoconductive element are contructed into a single kit. This kit is removable from the image recorder and replaced with a new one independently of the photoconductive element. A problem with this kind of image recorder is that when the kit is separated from the photoconductive element, toner collected in the cleaning unit is apt to be scattered around through an opening a collecting section of the unit because the opening is moved away from the photoconductive element, contaminating the interior of the image recorder. One approach for solving this problem is disclosed in, for example, in Japanese Laid-Open Utility Model Publication (Kokai) No. 57-195166. The approach disclosed in the Laid-Open Publication is such that a cleaning blade of a cleaning unit and a container adapted to store toner which is collected from a photoconductive element by the cleaning blade are constructed unitarily with each other. When the container is removed from the image recorder, the cleaning blade is elastically displaced and, in response to such a displacement of the cleaning blade, a closure member blocks the opening of the container. However, even this implementation fails to stop that part of toner which is deposited on the cleaning blade and its neighborhood. Another implementation is shown and described in Japanese Laid-Open Patent Publication (Kokai) No. 61-110168 and is comprised of an abutment member which, when a cleaning unit is moved away from a photoconductive element, closes an opening of a toner collecting section of the unit in place of the photoconductive element. This implementation, however, increases the overall dimensions of the image recorder while making the manual operation troublesome.
Another problem particular to an electrophotographic copier or the like designed for personal use is the removal of a paper jam. That is, when a paper jam occurs in such an image recorder, the user has to remove the jamming paper without the help of a serviceman. A clamshell structure is one approach to allow a person to remove a jamming paper, as well known in the art. Specifically, an image recorder with a clamshell structure is constituted by an upper and a lower unit which are located on opposite sides of a paper transport path. In this case, a photoconductive element and a process kit having other major process units therein are mounted in and movable integrally with the upper unit, facilitating easy removal of a jamming paper. In the clamshell structure, however, the process kit cannot be replaced with a new one unless the photoconductive element is temporarily taken out of the image recorder of the process kit itself is pulled out toward the person with the greatest possible care so as not to scratch the photoconductive element.